<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>

    <div id="app">
        <input type="text" id="input" v-model='msg'>
        <div id="box">{{msg}}</div>
    </div>



    <script src='./index.js'></script>
</body>
</html>